HISTOPATHOLOGICAL EFFECT INDUCED BY
DIMETHOATE ON LIVER OF ALBINO RATS
Dr. Mokshi Sharma1
, Dr. G K Sangha2
Department of Zoology, Punjab Agricultural University (India)
Pesticide hazards have been accentuated by the sharp rise in their agricultural, industrial and domestic use. The extensive use of dimethoate poses a health hazard to animals and humans because of its persistence in soil and crops. Our study investigated the toxic effects of the dimethoate at different dose level, an organophosphorous pesticide, on organ like liver of albino rat. Dimethoate was administered orally for one month at doses 1/20th, 1/40th and 1/80th on the basis of LD50. Half of the experimental animals were sacrificed and the rest were left to study the inbuilt capacity of the animals to metabolize the toxicant. Treated mice were showed many histopathological alterations in liver like, vacuolation, blood congestion, and high lymphocytic infiltration around the central vein, enlargement of hepatic sinusoids, hepatocellular damage, necrosis, and increase in number of kuffer cells, lessions and hemorrhage. However, these alterations were recovered in the next set of experimental animals showing the inbuilt capacity of the organism to metabolize the toxicant.
Dimethoate, Histopathology, Albino rat.
The environmental pollution is one of the most serious problems that faces mankind in this century. There are
many types of pollutants that interfere with our-life both directly and indirectly. Furthermore, potential future
hazards to human health and wildlife can be created by residues from some long-lived pesticides that may build
up in the food chain and cause widespread contamination of the environment (El-Sebae, 1993; Zaahkouk et al., 2000). Nowadays, the hazards of pesticides have been accentuated by the sharp rise in their use by farmers,
industrialists and householders alike. Pesticide poisoning resulting in death occurs mainly in developing
countries where the consumption of these products is high (Banerjee et al., 1999). Organophosphate (OP)
compounds are the most toxic pesticides causing environmental pollution and potential health hazards (Agdi et
aI., 2000). Being biologically active compounds, pesticides have been thoroughly tested for safety and usefulness prior to their agricultural use. However their misuse may cause drastic effects to humans, and the
environment (GIFAP, 1984).
Dimethoate, are the widely used systemic pesticides in agriculture against a wide range of insects, mites and
fungal diseases of fruits, vegetables, or namental plants and field crops as both systemic and contact pesticides
and are also used indoor to control houseflies (Meister, 1992; Farag et al., 2006; Brkic et al., 2008 and Muthuvivegandave et al., 2011). The irrational and excessive use of these pesticides plays a crucial role in the
chemicals and drugs. Hepatotoxicity is therefore an important end point in the evaluation of the effect of a
particular xenobiotic. Clinical chemistry and histopathological evaluations are commonly used methods for
detecting organ specific effects related to chemical exposure (Travlos et al., 1996; Crissmann et al., 2004). Dimethoate has acute oral toxicity of 150mg/kg by in mice and has been classified as moderately hazardous
(IPCS/WHO., 2001; Kidd, et al., 1991). Also, Poet et al., 2003, studied the effect of two organophosphorous pesticide on the hepatic and intestinal metabolism in the rat and found that the metabolizing enzymes
responsible for both the bioactivities and detoxification are present in the small intestine at lower level than the
liver but still significant. Also, Bulusu and Chakravartylndira et al., 1992, studied nucleic acid and protein
propel in normal and malnourished rat liver on exposure to organophosphorous group of pesticides and found
that were affected in both. Moreover it has been proven to accumulate in the testis where it persisted for weeks
even after oral administration was stopped (Afifi et al., 1991) and inhabited steroidogenesis primarily by
blocking transcription of the steroidogenic acute regulatory (STAR) gene (Walsh 2000). Few studies have been
made on the histopathological effects of dimethoate (Thangavel et al., 1994; Persis et al., 2001). The present studies have been aimed to investigate the histopathological effects of the dimethoate (an organophosphorous
pesticide) that is widely used in some agricultural areas in India on some organ of albino rat.
II. MATERIALS AND METHODS
2.1 Chemicals and Plant extract
All chemicals were purchased from SDFCL (SD Fine-Chem Ltd) and SRL (Sissco Research Laboratories Pvt
Ltd). All chemical used were either of analytical grade or the highest purity commercially available. Standard
rat feed was purchased from Ashirwad Industries, Mohali, India.
The female albino rats aging 9-12 weeks and weighing 140-170 grams were procured from the Department of
Livestock Production and Management, GADVASU, Ludhiana and were maintained in laboratory conditions
with standard pelleted rat feed and water provided ad libitum.The animals were kept in a room in which the humidity and temperature were environmentally controlled. All methods and procedures of animal handling
during research were conducted in accordance with the guidelines of Committee for the Purpose of Control and
Supervision of Experiments on Animals (CPCSEA), India and experiments conducted in the present study were
duly approved by Institutional Animal Ethics Committee (IAEC), Guru Angad Dev Veterinary and Animal
Sciences University, Ludhiana vide letter no IAEC/2014/125-53 dated 13/08/2014.
2.3 Experimental design
Female albino rats were acclimatized for ten days in laboratory conditions and were divided into eight groups
with six rats in each group.
Group I (Control) animals received feed + distilled water, olive oil and served as control
Group II 1/20th of dimethoate by oral intubation
Group III 1/40th of dimethoate by oral intubation
GroupV Olive oilfor15 days and left without any treatment for next 15 days then sacrificed.
GroupVI 1/20th of dimethoate for15 days and left without any treatment for next 15 days then sacrificed.
Group VII 1/40th of dimethoate for15 days and left without any treatment for next 15 days then sacrificed.
Group VIII 1/80th of dimethoate for15 days and left without any treatment for next 15 days then
At the end of 15 days, mice from exposed Groups (I, II, III & IV) were anesthetize and dissected, liver was
removed and fixed for histopathological investigations using 10% neutral formal saline. Tissue was processed
by routine histological techniques, sectioned at 6μm, stained with hematoxylin and eosin. Finally stained
sections were examined under the high magnifying microscope and subsequently micrographs were taken. At
the end of experimental period, rat from (Group V, VI, VII &VIII) were taken in batches dissected and
examined for histopathological investigations. O
3.1 Histopathological Study of Liver:
Sections from the liver were prepared from both control and treated mice and were examined under the high
magnifying light microscope. The microscopic observations were reported and the intensity of changes was
tabulated in Table 1, and presented by the Figs. 1. These changes include the presence of more endothelial cells
scattered among the hepatocytes and some vacuolation in the liver texture (Fig A to F). Some sections of liver
from mice of treatment groups (I to III) treated with dimethoate pesticides showed rupture in some hepatocytes,
many other sections of the treatment sets showed dense lymphocytic infiltration round the central vein and dark
stained hepatocytic nuclei indicating cell pycnosis. A number of hepatocytes were found to contain shrinked
nuclei, while the liver sections belonging to the metabolized groups showed minor changes represented by
group V to VIII. LI
Table-I Histopathological Changes observed in Liver
Parameter I II III IV V VI VII VIII
1 Congestion + ++ ++ + + ++ + +
2 Cell rupture No Mild Moderate Moderate No Moderate No No
3 Vaculation + +++ ++ ++ No + No No
Occasional ++ ++ + No ++ + +
5 Nuclear death No ++ + + No No No No
6 Hemorrhage No ++ + + No periportal
7 Enlargement of
control & portal
No ++ ++ + No Perivescular
9 Increase in the
of kuffer cells
No +++ ++ + No mild No No
10 Necrosis No ++ + + No Focal area
No ++ + + No No No No
12 Enlargement of
No +++ ++ ++ No Mild No No
No ++ + + No No No No
14 Hepatocytes whic h
may show variation
lipid Like bodies of
Normal +++ ++ + No Mild No No
The animal model used in this study was used to assess the adverse effects of pesticides on laboratory animals
(Costa et al., 1989). While, investigating the histopathological effects of dimethoate pesticides on Liver of
albino rat, the results showed mild to severe effects on the organ studied. Some significant results were found
while investigating the histopathological parameters. The Histology section of Liver showed to be more severely
affected by all the doses of dimethoate. The changes reported include lymphocytic infiltration, congestion,
nuclear death,enlargement of hepatic sinusoids, hepatocellular damage, parenchymatous cells showing
cytoplasmic vacuolation and degeneration in nuclei. To a bit extent, cell rupture, increase in kuffer cell
number,hemorrhage and some hepatocytes which showed variation in lipid like bodies of various sizes were
also observed. The role of liver in xenobiotic metabolism is very essential as it contains a large number of
enzymes responsible for xenobiotic metabolism. Accordingly as per its role it is more susceptible to chemical
injury (Sharkoori, Alam & Ali., 1990). Section through the liver showed chronic inflammation,congestion
which could lead to jaundice and death of hepatocyte (necrosis).In an earlier study, Khogali et al. (2005),
reported Dimethoate-induced hepatic pycnosis,vacuolation, blood congestion and high lymphatic infiltration
around the central vein; Thangevel et al., 1994 reported the toxic effect of an organophosphate pesticide dimecron and acarbamate fungicide cumin on the histology of liver showed the destruction of hepatocytes and
protrusion of nuclei. While oral administration of Carbosulfan at 48 mg/kg/day for 5, 10, 20 and 30 days in
albino mice resulted in dilation of central vein and sinusoids between hypertrophied hepatocytes,vacuolization
and hyalinization of hepatocytes with loss of radial arrangement, suggesting that theinsecticide had adverse
effects on liver functions leading to histological and physiological impairments (Ksheerasagar and Kaliwal,
2006). The lymphocytic infiltration observed in some controlled mice might be due to the groundnut oil or due
to the hygienic condition other than the chemical effects. Liver tissues from mice treated with high doses of the
dimethoate showed hepatocytic nuclear death or cell pycnosis. Similar effects were reported by Singh et al.,
(1994). The evidences of liver damage like cord disarray hypertrophy and disintegration of hepatocytes showing
different sizes of nuclei, lymphocytic infiltration, in addition to sinusoidal blood congestion and hemorrhage
was also reported by many investigators using various chemicals and toxicants with different animals including
fishes (Persis and Kalairasi, 2001; Abdu Rabou.,1996; Shakoori., 1992; Khogali 1989).Recently, El-bendary et
al. (2014) evaluated histopathological abnormalities associated with Profenifos and Chlorpyrifos exposure in
male albino mice where liver showed hepatic cell damage with degenerative changes including congestion of
blood vessels, vacuolar degeneration of hepatic cells, focal infiltration and mononuclear cells, dilated central
vein and other hepatic blood vessels, necrosis of hepatic cells, disorganized with the formation of denoid
structure and hepatocytomelagy; whereas kidney showed hemorrhage, oedema, necrosis and glomeruli
shrinkage. Since, the present feed treatments of albino rat with Dimithoate clearly demonstrated significantly
changes in the histopathology of hepatic tissue, it could be possible that prolonged exposure to this insecticide in
man may play a significant role in aggravating such diseases as chronic liver failure. In addition, structural
changes to hepatic tissue such as haemorrhage, congestion, vacuolation and erosion may also lead to acute liver
damage. The present results could thus be exploited as a potential biomarker of common insecticide toxicity in
The present findings clearly demonstrate that Dimithoate is capable of inducing dosedependent morphometric
i.e. histopathological change in the liver of the exposed rat. According to these data, it is suggested that systemic
insecticide like Dimethoate exposure might cause hazardous effects, especially at high doses, to man and
environment. For field and domestic uses of this insecticide, quantities and mode of usage need to be strictly
monitored to minimize the possibility of its exposure to non-target organisms including human beings. This can
be achieved through public health education to make people aware of the hazardous effects of this chemical.
Due attention also is to be paid for a delayed period of field application of this insecticide to avoid its possible
adverse effects to consumers, who should be warned of the potential risk of Dimithoate contamination of food
and drinking water in the country.
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